# Source code for spinn_utilities.helpful_functions

```
# Copyright (c) 2017-2018 The University of Manchester
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from functools import reduce
import logging
import inspect
import math
import re
from spinn_utilities.log import FormatAdapter
logger = FormatAdapter(logging.getLogger(__name__))
FINISHED_FILENAME = "finished"
[docs]def get_valid_components(module, terminator):
""" Get possible components, stripping the given suffix from their\
class names.
:param module: The module containing the classes to obtain.
:param str terminator:
Regular expression string to match the suffix. Anchoring not required.
:return: mapping from (shortened) name to class
:rtype: dict(str -> class)
"""
terminator_re = re.compile(terminator + '$')
return {terminator_re.sub('', name): router
for name, router in inspect.getmembers(module, inspect.isclass)}
[docs]def is_singleton(value):
""" Tests whether the value is a singleton.
Singleton types are strings and any other class that can not be
iterated.
Strings are considered singleton as rarely will someone use a String
to represent an iterable of characters
"""
return not hasattr(value, '__iter__') or isinstance(value, str)
def _lcm(a, b):
return (a * b) // math.gcd(a, b)
[docs]def lcm(*numbers):
"""
Lowest common multiple of 0, 1 or more integers.
GIGO: If any of the values are anything except positive int values
this function will either produce incorrect results or raise an exception.
:param numbers: The Positive integers to get the lcm for.
This can be zero, one or more int values or
a singleton which is an iterator (possibly empty) of ints.
:return: the lcm or 1 if numbers is empty or an empty iterator
:rtype: int
:raises TypeError: If any value can not be interpreted as an Integer
:raises ZeroDivisionError: May be raised if one of the values is zero
"""
if len(numbers) == 1:
try:
return reduce(_lcm, iter(numbers[0]), 1)
except TypeError:
return numbers[0]
return reduce(_lcm, numbers, 1)
[docs]def gcd(*numbers):
"""
Greatest common divisor of 1 or more integers.
GIGO: If any of the values are anything except positive int values
this function will either produce incorrect results or raise an exception.
:param numbers: The Positive integers to get the GCD for.
This can be one or more int values or
a singleton which is an iterator (not empty) of ints.
:return: the gcd or 1 if numbers is empty or an empty iterator
:rtype: int
:raises TypeError: If any value can not be interpreted as an Integer or
if no values are provided
:raises ZeroDivisionError: May be raised if one of the values is zero
"""
if len(numbers) == 1:
try:
return reduce(math.gcd, iter(numbers[0]))
except TypeError:
return numbers[0]
return reduce(math.gcd, numbers)
```